just check the total count of datasource you provided to your Radgridview like this...
if ADO.NET with Data Table then like this..
suppose Data Table is DT then
Dt.rows.count
or dataset then
suppose dataset is ds then
Ds.Table[0].rows.count
and suppose you are binding any list to your Rad Grid then
suppose list is ls then
ls.count
you can get total record count from your datasouce to display in your label.